There have been many prior attempts to design umbrellas which can be used in gusty conditions without risk of damage.
Umbrellas having compression springs mounted on the pole between the slider and an upper crownpiece from which the ribs extend are well known and commonly used. Although the springs provide a cushioning, upper stop or buffer which permits the canopy and ribs very limited upward movement as a whole in response to the force of a strong wind, controlled displacement of the canopy and the ribs as a whole above the horizontal, rain shedding position and, therefore, inversion of the canopy to spill the wind is not possible while the entire spring must be overcome to permit upward movement of even a single rib so that upward movement of only a portion of the canopy to relieve unevenly distributed wind stress is not possible.
Some other prior attempts have been directed to the prevention of inversion of the umbrella canopy, often by the provision of one or more canopies having wind escape apertures to prevent inversion.
In one prior approach taught by U.S. Pat. No. 4,979,534 to Johnson, upper and lower canopies have wind venting apertures formed therein, the upper canopy being secured by elastic members on the lower canopy covering the wind venting apertures thereof so that a wind upthrust will be vented through the lower apertures raising the upper canopy away from the lower canopy to expose the venting apertures in the upper canopy thereby releasing the wind force, the raising movement being accommodated by resilient flexure of the elastic members.